Design of Structural Frames to Deflexion Limitations

Queries from several members convince us that there is a prevalent misunderstanding about written comments on papers published in the Journal; many seem to believe that these are not acceptable, but this is not so. The miscomeption probably stems from the decision not to give notice of a closing date for written comment as was at one time done for each paper. The reason for this was that quoting a terminal date inhibited and suppressed worthwhile observations, many of which were not formulated in good time and consequently not submitted. Comment which makes a useful contribution is welcome at any time; obviously the sooner after the publication of the paper concerned the better, since it will be fresher in the reader's mind and probably more readily accessible. Nevertheless, good comment is always useful no matter how far removed in time from its stimulus, and it must often be that grounds for comment do not become apparent until some application reveals a flaw, an inconsistency or, for that matter, a confirmation. Apart from the normal submission of comment to the Editor, there is lways this column in which we will be glad, as we always have been, to air the observations of members, anonymously if they so wish. Verulam

A new ultimate load method of design is presented which can be used for predicting the failure load of conventional plate girders having webs reinforced by both longitudinal and transverse stiffeners, hybrid girders and unsymmetrical girders. This new design method provides identical lower and upper bound solutions, and, furthermore, it is shown that many of the existing solutions are contained as special cases of the present, more general solution. D.M. Porter, K.C. Rockey and H.R. Evans

Situations are described in which it is advantageous to use composite steel-concrete beams with fewer shear connectors than the number required for full interaction. From a study of the results of tests and computations, simple rules are derived for estimating the ultimate flexural strength of such beams, and for checking deflexions in service, both by calculation and by the use of limiting span-depth ratios. R.P. Johnson and I.M. May